Method for the preparation of sulphur dyes



Patented Oct. 20, 1931 v v -ME'rn0n roamnnrREPARATIon or sULrnUn aYns f1 NopIl J rawiiigl 1 J- l This invention relates to a method for the preparation of sulphurdyes (more especially dyes of this type which shallbe characterized by a ready and complete solubility in -Water), anditothe product resulting therefrom." r I i It isWellknoWn in the art of' mak ing dyes stufl's that nitroor amino-aromatic comm pounds in general some other nitrog- 1 enous aromatic compounds) are readily reacted'upon by an alkali metal sulphide and free sulphur or by the alkali metal poly sulphidesto form addition orpolymerized comr n pounds, possessin'gtlie characteristics of dyer 7 a I stufls and having a range of'colors lnoludbath from Which they are deposited on the cloth, (either directly or upon drying-and oxidizing in the air) to form a relatively fast-coloredmaterial i The use ofsuch strongly alkaline solutions,

however, :tendsto attack the textile; fibers and to vveakenthem moreo'r' less, eitherbe fore or simultaneously with thedyeing re-I action, thus leaving the. dyed fabric some What tender or brittle, Moreover, it is diflicult' and expensive to prepare such alkali metal sulphide solutions of. predeterr'nined t3 composition and in the properly "p roportioned concentrations and amounts with res'pectjto thedye substance. In fact, it usually requires a preliminary series'of tests to estab 1 lish'the most satisfactory"conditions,and these conditions may""vary with diflt'erent batches of a'singledyestufl'. ,Moreover, it

requiresv constant adjustment and 7 control .to

maintain the effective relative concentrations co nstant in a given solution, vvithfrespect:

" te-either the quantityof dye substance or I the alkalinity of the dye bath.

, It is accordinglyan ob ect of this invention to provide a sulphur dye which is directlytextiles and" like materials has'heretofore re-f ce'dureI It is amnaj at to ima e the.

efficienjcyof manufacture "and toimprovethe' Y efliciency of dyeing with the ultimate'product 1 obtained, Other objects will appeanfrom' the disclosure. 1 I

The invention, generally stated, includes the discovery that sulphur dyesf (as more; specifically defined. above) and'more 'particu if larly'sulphur black, asmade byjthelusual processes heretofore known, maybe fhydrosoled, so-called, or converted intoa Water 1' solublesulphur and/or sulphideii-addition compound by tre'ating -with analkali metal sulphide, vunder suitable reaction conditions, such as by heating thereaction mixture or{ solution (with OP-Wl-thOilt pressure) out of contact, with oxidizing gases. -(e.r g., in vacuum ,or in an atmosphere of'inertgas). Thef latter condition (o'f'inertgases orivacuu'm) .is preferably continueduntilthe 70.

become dry and hard; As ordinarily. obtai'ed,1in heusualcourse' of manufacture, and-beforeithe originalsul I v 1 phur dyehas b'eenfthoroughly driedi' oriper};- mitted'to harden, it is founddesirable if'l not 7 i essential (for the purposesoiE-thepresent; nv n o "to u e the' ha se to 1a relativelyi thorough washing. to memoveflsolubleg salts or other "impurities which may be I formed as contaminant ,by-pr'oductsand em P trained with the lesssoluble orinsoluble'dy.

substance. This isbest 'donel with water and. by addition of small amountsfi Sometimes the-washing may be more readily "andcom;

pletely efl'ected by thoroughly drying thedye substance, Qpulverizi'ngr and theniwashing'." The washed sulphur color is then 'subjeotedto; the treatmentdescribed An exam leyef thejadaptation bathe; a, Q ventionto a specific instance o'fits practical 9 a applicationin thejartsvvillbe' descr'bed reference to sulphur black.

"A common method forthepreparationofj Q s'ulphurblack invol'vesthe treatment ofa di substituted phenol compound or ofa tri-substituted benzene orlike compound typically,

containing one or more nitrogen atoms in its molecular constitution, with an alkali'm etal soluble in Water and a method forprep'aring sulphide or polysulphide' s under heatan'd,

the same upon a commercial scale of"pro-ipressure).whereuponan addition or substitum alkali metal polysulphide.

tion takes place in which the sulphur and possibly also a part of the sodium go into combination with the aromatic nucleus and form sulphur black. This reaction may be accompanied by polymerization also although the precise nature of the chemical. reaction or reactions involved is not fullynor-certainly understood. Nevertheless, the general course of the reaction is common to reagent compounds of the type described and results in the formal ion of a compound capable of serving as a dye for textile and like materials under alkaline conditions; U

As thus produced, the sulphur color is not soluble in water, nor will it serve for the direct 'eing of textile fibers, but is readily dissolve in an aqueous solution of sodium sulphide,"forexainple, and thereupon becomes capable of dyeingcotton and the like very L readily and imparts a fast black theretoL Such a (black) dye may be prepared from (1-24) dinitrochlor benzol by first heating in an aqueoussolutionewith two molecular equivalents of sodium hydroxide and then treating the'alkaline reaction product with an The solution is then d1luted' blown with air. This decomposes the sulphide and the dyestuit is thrown downas a heavy black precipitate. It .is then filtered or otherwise separated from the supernatant liquid as well as the soluble reagents or byproducts contained therein. It may be furth er washed with water and then filter. pressed or otherwise separatediromihe 'washings.

1 The sulphur black sludge press cake obtained is now added to an aqueous solution of alkali metal sulphide. This may be the normal sulphidejas indicated by the formula Na s or itfmay contain a greater proportion of sulphur (Na SQor a lesser proportion of suluhur. (Na- S) as maybedesire'id. Forthis.

purpose, the sodium sulphide may be mixed withequal'parts of water and heated to 100 C, and the sulphurblackadded slowly, the

temperature being maintained during the addition and for one ortwo hours thereafter.

That a. chemical reaction takes place is made manifest by the evolution of he at at this stage of the operation as well as by the new anc tained. I V ,7 It is found that the amount of sodium sulimproved properties of a the product ob- .ta phide which can be a ddedto a given quantity of the sulphur black may be controlled in terms of the strengtlrofgthe dyestufi'. Thus, adopting a fixed dye strength for a standard blac'k as 100, (determined by a test of its actual dyeing capacity) a, given addition of sulphide (e. g., varying from to of the color substance by'weight) may prove to bemost satisfactory. If, now, a given sample of dyestuff manifests a dye strength of 90% of the standard the addition of sulphide vith water and r and heated, as steam-coils, to a temperature of approximately 130 0., while the space above the pans is evacuated and maintainedwith avacuum of approximately 26 inches of mercury for eight hours. Alternatively, the atmosphere of the dryingchamber vmay bedisplaced by an inert, non-oxidizing gas to prevent simultaneous oxidation of the dye substance during the drying operation. In

either procedure,that is, either with or without superposed pressure, the drying maybe accomplished at relatively low temperatures and thus with a minimized tendency toward the decomposition of the dye substance or compound. i

The finished product is usually hard and brittle and may be crushed and ground in any convenient way, the resulting granules or powder, being rapidly and completely soluble in water and of substantially uniform composition and color strength. Moreover, it is especially suitable for the direct dyeing of the various textile fibers by dissolving in Water and applying the resulting solution directly to the 'materiaL-OtherWise in accordance with thecustomary known practices of the art. I 'Morcover, the coloring or dyeing qualitiesof thecolor substances are greatly improved and it does not require the addition of alkali or alkalimetal sulphide to the dyeing bath '(although they may conveniently be used) but forms a dye solution of uniform and readily controlled concentration which is substantially inert with regard to the, strength of textile, fibers upon whichit may be employed. Accordingly, the extra expense of labor and materials in preparingand adjusting thedye bath. are eliminated and the concentration of the dye bath is directly de-' termined by the amount of dyestuif which is added thereto. A further economy is realized from the fact that althoughthe total weight of dye/substance produced is increased by this addition'of alkali metal sulphide and/or sulphur, the dyeing quality or strength per unit of. weight of the finalproduct is not proportionately decreased but is, in fact, equal to or greater than that of the untreated sulphur color. p

It is further observed, if the'procedure is carried out, that with increased proportional amounts of sulphur, (e. g. in excess of that corresponding to the, normal sulphide,

Na s) the greater is the amount of sulphide which may be combined with the color substance. Thus, results of the following order have been obtained Increased S Q 1 Free S added in product 7 Trace. 2. 2. O. 5 3

Likewise, with increasedproportions o1 sulphide the Weight of color substance is increased.

But this increase in the yield of color product produced is not obtained at the expense of the dyeing or color strength per unit of weight, .for thelatter may be and usually is greatly improved along with the other advantages and improvedfactors obtained by the invention. r

Ordinary dyeing method: 100 parts sulphur black and IOOparts Na s yield 100 dye units. i

tively.

4. A method for the treatment of sulphur,

blackwhich comprises subjecting the color. substance to reaction with to 70% of sodium sulphide and additional quantities of sulphur, and drying the same under vacuum.

' V 5. A method for thetreatment of sulphur black which comprises subjecting the color substanceto reaction with alpredetermined quantity of sodium sul hidein proportions varying from 35% to 0% and additional" bluish and greenish shades of black, respec- I quantities'of sulphur, and drying the same.

under vacuum, whereby a soluble black ,is

producedof reddish to bluish and greenish shades of black, respectively. Signed by'me at Boston, this18th day. of January, 1927.

Present method: 100 parts sulphur black with 50 parts Na s yield 150 parts water soluble black dye.

Upon dyeingwith the latter as'in theordinary method, using 150 parts Na S,yields 150 dye units.

That is, 200 parts Na s instead of 100 parts of Na s produces 50 dye units for the 100 partsof Na s additional.

It will be readily appreciated by those a skilled in the art of manufacturing and applying dye substances, that various modifications, adaptations and substitutions may be resorted to in the application of the in- I vention in theseveral artsto which it is related. Such modifications and substitutions are, however, to be understood as comprehended by the above disclosure and'included within the terms of the following claims.

I claim: e 1. A water soluble black dye characterized by being composed of the reaction product of sulphur black with sulphur and 35% to of alkali metalsulphide, and by being readily and completely soluble inwater.

2. A method for the treatment of black which comprises subjecting the color substance to reaction with 35-70%, sodium sulphide and additional quantities of sulphur, and drying the same under inert 'at-' mospheric conditions. e

3. A method for the treatment of sulphur black which comprises subjecting the color sulphur I Massachusetts,

ALBERT c. BURRAGE, JR i I 

